Insulated terminal for transformers and the like.



C. H. THORDARSON. INSULATED TERMINAL FOR TRANSFORMERS AND THE LIKE.

APPLICATION mu) FEB. I0. 1915.

Patented Feb. 13, 1917.

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CHESTER H. THORDARSON, OF CHICAGO, ILLINOTS.

I [NSULATED TERMINAL FOR TRANSFORMERS AND THE LIKE.

Application filed'February 10, 1915.

To all whom it may concern:

Be it known that I, CHESTER H. THORDAR- SON, a citizen of the United States, and. a resident of Chicago, in the county of Cook and State of Illinois, have invented certain This invention relates to insulated terminals for high potential electrical transformers and like high potential devices, and the invention consists in the matters hereinafter set forth and more particularly pointed out in the appended claims.

Among the objects of the invention is to provide an insulated terminal for high potential transformers and like devices of a construction to Withstand heavy electrical stresses, and which is also so constructed as to withstand mechanical and thermal stresses without danger of breakage.

A further objectof the invention is to provide a novel means for making up a' eomposite terminal of the character descrlbed by which the parts of the tBIIl'llIlfl-l' may be completely assembled in the shop and may Figure 1 is an aiio s ct-ion be readily applied to the receptacle in the field without the necessity of deranging the shop assemblage.

A further object of the invention is to provide a composite insulated terminal for the purpose set forth of such character as to automatically compensate itself to irregular thermal and mechanical stresses, such as would ordinarily tend to disrupt essential electrically insulating and mechanical parts of the terminal.

A further object of the invention is to provide a construction of terminal of this character which may be made at a reduced cost as compared to prior terminals for a like use and in which the likelihood of breakage of essential parts of the terminal is greatly reduced.

Other objects of the invention are to simplify and improve terminals of this character, and .to provide a terminal having a low corona (i harge.

Inthe diawings:

a, of high po- Specification of Letters Patent.

Patented Feb. 13, 1917.

Serial No. 7,232.

tential insulated terminal embodying my invention.

Fig. 2 is a fragmentary view of a transformer or like casing showing the manner in which the terminals are applied thereto.

A terminal embodying my invention comprises as its main or principal elements a conductor rod 10 of usual form which extends from the exterior to the interior of the receptacle 11 to which the terminal is adapted to be applied, an insulating tube 12 which surrounds the conductor rod, and a porcelain'or like casing designated as a whole by 14 which surrounds the insulating tube 12.

The insulating tube 12 is preferably made of a material which is more or less yieldable, such as a fiber or paper sleeve The exterior casing is rigid, it being preferably made of;

porcelain or the like. The said exterior casing is exteriorly shaped in its part above the top wall 13 of the receptacle 11 to constitute so-called petticoat insulator flanges 15.

In accordance with one phase of my invention said flanges 15 constitute parts of separately formed tubular sections 16 which are applied over the insulating tube 12 and are nested thereon in the manner shown in Fig. 1. Preferably said sections 16 of the casing 14 are joined along downwardly and outwardly oblique annular surfaces, and the joints between adjacent sections are desirably filled with a suitable cement filling 18 to avoid the entrance of water between the sections to the insulating tube or sleeve 12. The said sections 16 are furthermore formed with curved projections 19 at the outer edges of the joints so as to afford water sheds to further guard against the entrance of moisture to said joints.

The lower portion 20 of the body of the casing 14 may be made integral from a point above the receptacle wall 13 to the lower end of the device, which latter, in its use with a high potential transformer extends below the oil level indicated in Fig. 2. The said body portion 20 is provided at the level of the wall 13 with an annular recess 21 to receive an annular body of cement 22 or the like which latter is surrounded by a bushing 23 by which the device is adapted to be locked in the perforated top wall 13 of the receptacle 11; the bushing being locked in place by a screw-threaded nut 24 that cooperates with the head of the bushing as indicated in Fig. 1. The ring 22 of cement carries more or less moisture, and it is preferable to form the wall of the recess as a relatively long curve so as to thereby reduce the corona discharge. Preferably a sealing ring or washer 25 of any suitable water-proof material is interposed between the head of the bushing and the upper face of the said top wall 13 to prevent the entrance of water'into the casing through the terminal open.

In accordance with another phase of my invention the parts of the terminal may be assembled as follows; The conductor rod 10 is screw-threaded atits upper and lower ends to receive nuts 26, 27, respectively, between which the leads 28, .29, respectively, are clamped to electrically connect them to the conductor rod 10. Between the upper end of the insulating tube 12 and the upper section 16 of the sectional casing 14 and the lower one of said nuts 26 is interposed a resilient connection which consists, in the present instance, of upper and lower spring washers 30, 31, respectively. The said washers loosely surround the conductor rod 10. The lower washer 31 is arranged in a downwardly and outwardly inclined position and engages the inclined or conical upper surfaces of the insulating tube 12 and the upper section 16 of the casing 14. The upper washer is engaged near its central opening by the lower nut 26 and is inclined downwardly and outwardly for engagement at its lower edge with the upper marginal portion 33 of the washer 31. The periphery of the lower washer 31 is upturned, andthe periphery of the upper washer is curved downwardlyto engage overthe upturned periphery of the lower Washer so as to form a waterproof joint between the parts and to also provide a rounded contour at this point to reduce the corona discharge. This construction also provides a resilient connection between the nuts 26 and the upper ends of the tube 12 and the casing sections 16.

At the lower end of the terminal there is provided in engagement with the upper nut 27 a washer 35 which surrounds the lower end of the conductor rod 10 and which is provided with an upturned peripheral flange 36. Surrounding the lower end of the conductor rod 10 and engaged with the lower end of the insulating tube 12 is a narrow washer 37 which is preferably provided with a downturned retaining peripheral flange 38. Engaged with the lower end of the body portion 20 of the casing 14 is another washer 39 that is provided with a peripheral, downturned retaining flange 40. Between the said washer 35 and the superjacent washers 37 and 39 are interposed helical compression springs 41, 42, respectively, which, when the nuts 27 are turned up against the lower washer 35 serve to BEST AVAILABLE OOH transmit a yielding retaining pressure against the lower ends of the said insulating tube 12 and the insulating casing 14, respectively. This pressure is exerted independently against said parts by reason of the fact that the actions of the two springs 41 42-are independent each of the other.

From the above description, it will be noted that the sectional casing 14 and the insulating tube 12 are yieldingly held in assembled relation so as not to exert on the inclosing, relatively fragile, casing 14 a stress tending to break the same. Moreover,

.the material of the insulating sleeve 12 is in itself to an extent yieldable to avoid any undue stress against the more fragile portion, such as the casing 14 of the structure, due to thermal and mechanical strains.

By reason of making the exterior casing 14 in sections and oining them in the manner shown, the fragile portion of the insulator is less likely to break than if the entire casing be made of one piece, so that, thereby, the cost of producing the'insulator is substantially decreased as compared to prior V practice.

It will be noted that the entire device including the bushing 23 may be assembled at the factory and may be readily placed in position in the field by merely removing the r the spirit and scope of the invention, and the invention is not limited to such structural details except as made the subject of specific claims and as imposed by the prior art.

I claim as my invention:

1. An insulated terminal for high potential transformers and the like comprising, in combination with a conducting element, a yieldable insulating tube surrounding the same, a rigid insulating casing surrounding said tube from end to end and yielding clamping means cooperating with the ends of the tube and easing.

2. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same, a rigid insulating casing surrounding said tube and yielding holding means acting endwis'e" against said tube and said casing to lpold them inassembled relation..-::-

- 3. An insulated ternrinal for high potential transformers and the like comprising, in combination with a conducting element, a yieldable insulating tube surrounding the same, and a rigid sectional casing surrounding said tube, with yieldable clamping means acting against the ends of the tube and casing for holding the tube and the casing in assembled relation.

4. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same, and a sectional casing of rigid material surrounding said tube, with means for holding the tube and the casing in assembled relation, the casing sections meeting in annular joints disposed obliquely to the axis of the terminal.

5. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same, and a sectional casing-of rigid material surrounding said /tube, with means for holding the tube and the casing in assembled relation, the casing sections meeting in annular joints disposed obliquely to the axis of the terminal and said sections being provided with petticoat flanges which overlap said joints.

6. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same and a casing surrounding the tube, said casing being provided between its ends with an annular recess, an attaching bushing surrounding said recessed portion of the casing, and an annular body of cement between said casing and bushing.

7. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same and a casing surrounding the tube, said casing being provided between its ends with an annular recess, an attaching bushing surrounding said recessed portion of the casing, and an annular body of cement between said casing and bushing, the wall of said recess being formed \b y a long curve to reduce the corona discharge thereat.

8. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same, a casing of rigid insulating material surrounding said tube,

nuts screw-threaded to the ends of said conducting element, and acting against tube and casing to hold them assembled, and separate springs between the nut at one end of the conducting element and said tube and casing, respectively.

9. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same, a casing of rigid insulating material surrounding said tube, nuts screw-threaded to the ends of said conducting element, a washer engaging the nut at one end of said conducting element other washers bearing against the respective adj acent ends of said insulating tube and casing, springs separately interposed between the first mentioned washers and said other washers and an abutment for the opposite ends of said tube and casing.

10. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same, a casing of rigid insulating material surrounding said tube, nuts screw-threaded to the ends of said conducting element, separate yielding connections between one of said nuts and the adjacent ends of said tube and casing, and two washers surrounding said conducting element between the other ends of said tube and casing and the other nut and having yielding peripheral engagement, for the purpose set forth.

11. An insulated terminal for high potential transformers and the like comprising a conducting element, a yieldable insulating tube surrounding the same, a casing of rigid insulating material surrounding said tube, nuts screw-threaded to the ends of said conducting element, separate yielding connections between one of said nuts and the adjacent ends of said tube and casing, and two washers surrounding said conducting element between the other ends of said tube and casing and the other nut and having yielding peripheral engagement, said washers having meeting curved peripheries engaged to form a waterproof joint and rounded to lessen corona discharges under electrostatic pressure.

In testimony, that I claim the foregoing as my invention I affix my signature in the presence of two witnesses, this 1st day of February, A. D. 1915.

CHESTER H. THORDARSON.

Witnesses W. L. HALL, Gr. E. DOWLE.

- Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

